Completely resorbable connective tissue distraction devices and techniques

ABSTRACT

A method for early stabilizing of distracted connective tissue. A distraction site is at least partially covered with biodegradable, bioerodible or bioresorbable materials before a distraction procedure takes place. Distraction is performed on a connective tissue at the distraction site. The distracted connective tissue is stabilized using the biodegradable, bioerodible or bioresorbable materials.

REFERENCE TO RELATED APPLICATION

This application is a divisional of application Ser. No. 13/454,622,filed Apr. 24, 2012; a continuation of application Ser. No. 10/920,505,filed Aug. 18, 2004; and a divisional of application Ser. No.09/733,287, filed on Dec. 8, 2000, which claims the benefit of priorityfrom Application Ser. No. 60/170,011, filed Dec. 9, 1999. The entirecontent of these U.S. applications are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention generally related to devices and methods ofdistraction, particularly of connective tissue such as bone, such as ina human subject. Preferably, the devices and methods are used in humancraniofacial bone distraction.

BACKGROUND OF THE INVENTION

Connective tissue is the tissue that binds together and supports thevarious structures of the body. It has been demonstrated that gradualapplication of force separating two or more portions of a canine orhuman connective tissue structure will result in deposition of extracellular fibrous tissue components with permanent increase in tissuesize and mass. E.g., Karp, N. S., McCarthy, J. G., Schneiber, J. S.,Sissons, H. A., and Thome, C. H. M., “Membranous Bone Lengthening: ASerial Histological Study,” 29 Ann. Plast. Surg. 2-7 (1992); andCostantino, P. D. and Freidman, C. D., “Distraction Osteogenesis,” 24Otolaryngologic Clinics of N.A. 1433-43 (1991) (“Costantino et al.”). Insome instances this has been facilitated by cutting or breaking thetissue intermediate the tissue areas where force is applied byperforming an osteotomy or corticotomy. In other instances, particularlyinvolving growing tissue, such cutting or breaking is not necessary.

For instance, human bone lengthening by gradual distraction wasdemonstrated at least as early as 1905, but it has been more widelypracticed only more recently, having been popularized by Ilizarov inRussia and De Bastiani and his associates in Italy. See McCarthy, J. G.,Schneiber, J., Karp, N., Thome, C. H., and Grayson, B. H., “Lengtheningthe Human Mandible by Gradual Distraction,” 89 Plast. And Reconstruct.Surg. 1-8 (1992) (“McCarthy et al.”); and Ilizarov, “The Principles ofthe Ilizarov Method,” 48 Bull. of the Hospital for Joint DiseasesOrthopaedic Institute 1-11 (1988). Gradual distraction offers distinctadvantages as compared to bone grafting. Taylor, Discussion of McCarthyet al., 89 Plast. and Reconstruc. Surg. 9-10 (1992):

It provides new living bone of similar character, the soft tissues arelengthened without loss of sensation, there is no donor-site morbidity,and the technique may stimulate the efficiency of the reduced functionalmatrix in the region. Id. at 10.

Most bone lengthening and corrective work has been done with respect tolong bones in the arms and legs, although McCarthy, et al. havedemonstrated that the mandible of human children can be lengthened bygradual distraction. See also Senezer, M., “Mandibular Lengthening byGradual Distraction,” 92 Plast. and Reconstruct. Surg. 372 (1993)(reporting lengthening of human adult mandibles).

Additionally, devices utilizing screw or other expansion mechanismsattached between and solely to the left and right maxillary teeth havebeen used in procedures that enlarge human palates. E.g., Epker, B., andFish, L., 2 Dental Facial Deformities 818-875 (1986). At least some suchprocedures commence with substantial expansion of the maxilla during theinitial surgical procedure. Id. at 831.

The mandibular distraction device utilized by McCarthy, et al., is arelatively large appliance mounted outside the patient's mouth on pinsthat pass through incisions in the cheek. Such distraction devices areheavy, unwieldy, unsightly and subject to damage or dislocation impact.Furthermore, such devices require incisions that leave scars that may beunsightly and require revision.

As McCarthy et al. have noted, better mandibular distraction devices areneeded for these and other reasons. See also Costantino et al. at 1441;and Karp, N. S., Thorne, C. H. M., McCarthy, J. G., Sissons, H. A.,“Bone Lengthening in the Craniofacial Skeleton,” 24 Ann. Plast. Surg.231, 236 (1990). Furthermore, gradual distraction of other craniofacialsites is desirable but generally has not been possible because of thelimitations of existing devices.

Early midface distraction with buried devices were being performed invarious centers by about 1993 (Cohen et al., J. Craniofac. Surg. 6:368etc. (1995); Muhlbauer, Reconstructive and Aesthetic Surg. Meeting,Yokahoma, Japan, April 1995 (abstract)). Molina performed high Le Fort Iosteotomoies and midface distraction by a reverse headgear that had thecharacteristics of a tooth-borne appliance (Molina, Workshop onDistraction of the Craniofacial Skeleton, New York University MedicalCenter, New York, N.Y., Mar. 18-19 (1994)).

In addition, buried midface distraction was performed in a child withanophthalnia and left craniofacial micrisomia (Cohen et al., Craniofac.Sur. 6:368 etc. (1995)). In this instance, the outcomes were documentedby cephalograms and coronal or three-dimensional computed tomographicscans. Muhlbauer conducted a series of Le Fort III and monoblocdistraction in patients with Apert's syndrome (International Meeting ofPlastic, Reconstructive, and Aesthetic Surgery in Yokohama, Japan(1995)).

Chin and Toth reported buried distraction, including Le Fort IIImidfacial advancement (Chin and Toth, J. Oral Maxillofac. Surg. 54:45etc. (1996)). Polley et al., using an external traction appliance,showed frontofacial advancement in a newborn with proptosis and upperairway obstruction (Polley et al., J. Craniofac. Surg. 6:421-423(1995)). Buried modified Le Fort III midface advancements having cleftlip and palate with midface hypoplasia and Class III maloccluson havebeen performed (Cohen et al., Plast. Reconstr. Surg. 99:1421-1428(1997)).

In these cases, transverse maxillary expansion was performed withsagittal distraction and in one case serial distractors were used toprovide vertical and horizontal distraction vectors. In other cases, asubtotal cranial vault reshaping and monobloc facial advancement wasperformed in a child who had Pfeiffer's syndrome and coreal exposure(Cohen et al., Plast. Reconstr. Surg, 101:1919-1924 (1998)).

In that case, after 28 mm of distraction, the proptosis was largelycorrected. Chin and Toth have reported Le Fort III advancement withgradual distraction using internal devices in a series of patients usinga method of rapid distraction (Chin and Toth, Plast. Reconstr. Surg.100:819-830 (1998)).

Polley and Figueroa reported the management of maxiallary deficiency inchildhood and adolescence by performing distraction osteogenesis with anexternal adjustable, rigid distraction device to provide improvement incleft lip, cleft palate and severe midface retrusion (Polley andFigueroa, J. Craniofac. Surg. 78:181-185 (1997); See generally Cohen,Seminars in Orthodontics, 5:52-58 (1999)).

Additional explanation of the conditions addressed by the presentinvention and, in some instances, more specific information about priorremedial practices is set forth together with the descriptions ofexemplary embodiments of the present invention provided below.

SUMMARY OF THE INVENTION

An embodiment of the invention is directed to a method for earlystabilizing of distracted connective tissue. A distraction site is atleast partially covered with biodegradable, bioerodible or bioresorbablematerials before a distraction procedure takes place. Distraction isperformed on a connective tissue at the distraction site. The distractedconnective tissue is stabilized using the biodegradable, bioerodible orbioresorbable materials.

Another embodiment of the invention is directed to a method for earlystabilizing of distracted connective tissue. A distraction site is atleast partially covered with biodegradable, bioerodible or bioresorbablematerials before a distraction procedure takes place. The biodegradable,bioerodable or bioresorbable materials include at least two pieces.

A first implant and a second implant are attached to the distractionsite. The first implant and the second implant are engaged with asliding expansion mechanism. Distraction is performed on a connectivetissue at the distraction site. The at least two pieces move withrespect to each other performing the distraction. The distractedconnective tissue is stabilized using the biodegradable, bioerodible orbioresorbable materials.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of embodiments and are incorporated in and constitute apart of this specification. The drawings illustrate embodiments andtogether with the description serve to explain principles ofembodiments. Other embodiments and many of the intended advantages ofembodiments will be readily appreciated as they become better understoodby reference to the following detailed description. The elements of thedrawings are not necessarily to scale relative to each other. Likereference numerals designate corresponding similar parts.

FIG. 1 is a perspective view depicting the two portions of atransmitting means being engaged using PLA/PGA screws.

FIG. 2 is a plan view depicting two transmitting means of FIG. 1 engagedwith an expansion means.

FIG. 3 is a perspective view depicting the nature of the engagement ofthe transmitting means and the expansion means as reversible.

FIG. 4 is a perspective view depicting the distraction device in placeat the site of osteotomy. The transmitting means are secured to theskull using PLA/PGA screws in holes drilled into the bone. During adistraction procedure, the implementation of the distraction devicewould be complete. Distraction would be accomplished by engaging theexpansion means with an activation means to gradually increase thedistraction distance.

FIG. 5 is a perspective view depicting the distraction device afterdistraction has taken place. This figure depicts a mock-up skull, thusthe distraction space has not been filled with distraction tissue. Atthe point in the procedure, the expansion means would be removed bydisengaging the expansion means from the transmitting means, such as byengaging the activation means to decrease the length of the expansiondevice. The expansion means can be removed using surgical procedures,preferably endoscopic procedures. If the expansion means is made inwhole or in part of biodegradable, bioerodible or bioresorbablematerials, then the expansion means can optionally be removed.Optionally, at least one stabilizer can be inserted into, over or aroundthe expansion space and appropriately secured such that the distractedtissue is mechanically stabilized. Such stabilizer(s) are preferablymade at least in part of biodegradable, bioerodible or bioresorbablematerial, such as PLA/PGA, preferably macroporous PLA/PGA.

FIGS. 6A, 6B and 6C are top, bottom and side views depicting aflange-engaging structure of a transmitting means of one aspect of thepresent invention that includes structures to engage an expansion means.

FIG. 7 is a conceptual diagram depicting the use of stabilizing means ina distraction procedure.

FIG. 8 is a conceptual diagram depicting the use of guiding means todirect the vector of distraction.

FIG. 9 is a conceptual diagram depicting the use of stabilizing means ina distraction procedure.

FIG. 10 is a conceptual diagram depicting the use of engagingstructures, such as in a “shark's tooth” configuration, that allowsmembers of the distraction device to slide against each other in aunidirectional manner, which can also serve to stabilize the distractiondevice itself.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Definitions

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Where a term is provided in thesingular, the inventors also contemplate the plural of that term.

“Connective tissue” as used herein shall mean the tissue that bindstogether and supports the various structures of the body. In particular,“connective tissue” includes collagenous, elastic, mucous, reticular,and cartilaginous tissues, and preferably includes osseous tissue andbone.

A “transmitting means” refers to a structure that is preferably attachedto a tissue region that is to be involved in a distraction procedure.The transmitting means can be made of any appropriate materials,including, but not limited to metals, ceramics, glass, bioglass,biodegradable, bioerodible, bioresorbable materials and the like.Preferably, a transmitting means is made of a biodegradable, bioerodibleor bioresorbable material, such as the material described in U.S. Pat.No. 5,919,234 to Lemperle et al., issued Jul. 6, 1999, and as availablefrom MacroPore (San Diego, Calif.).

Additional materials include lactic acid polymers as they are known inthe art, such as PLAGA or PLA/PGA (poly-(lactic acid-glycolic acid)).Any appropriate biodegradable, bioerodible or bioresorbable materialscan be used, so long as they have the desired characteristics, includingbiocompatablility and strength. Although the materials described in U.S.Pat. No. 5,919,234 are perforated, that is not a requirement of thepresent invention. Additional materials, such as PLA/PGA can also beused.

Moreover, a transmitting means is preferably heat malleable such thatthe material is malleable at a temperature above that of the normal bodytemperature (such as a glass transition temperature at about 55° C. to57° C. or greater, though the invention is not limited to such ranges oftemperatures) and is rigid at body temperature (such as about 55° C. to57° C. or less, though the invention is not limited to such ranges oftemperature). The glass transition temperature of the material ispreferably such that the malleable material, when contacted with atissue or organ, that tissue or organ is not appreciably damaged.

A transmitting means 10A, 10B (collectively 10) can be made of one ormore components that can be engaged to form a transmitting means, suchas set forth in FIGS. 1 and 2. The transmitting means preferably engagesan expansion means such that distraction is enabled by separating afirst transmitting means 10A from a second transmitting means 10B by anexpansion means 12 such as set forth in FIG. 2.

The transmitting means can be of any appropriate configuration, such as,for example, plates, stents, meshes or implants of any appropriateconfiguration. The transmitting means can have any appropriate shape,such as circular, oblong, polygonal, square or rectangular and can becut to fit using appropriate cutting devices, including shearing devicessuch as scissors, or heating devices, such as a wire heated to anappropriate temperature to cut or trim the transmitting means.

A transmitting means can be attached to a tissue region using anyappropriate attachment structures, devices or means, such as, forexample, screws, staples, tacks, pin, nails or implants of anyappropriate configuration or the like, wherein such materials can bemade of any appropriate material, preferably made at least in part of abiodegradable, bioerodible or bioresorbable material.

A “tissue region” includes a region of tissue to which a transmittingmeans is attached by an appropriate method, device or structure.Preferably, two tissue regions are adjacent to a site to be distracted.Preferably, a tissue region is a connective tissue, more preferablybone.

An “expansion means” refers to a device for expanding or contracting atleast two transmitting means of the present invention. Preferably, theexpansion means is a screw expansion mechanism. One skilled in the artwould recognize that other mechanisms, either alone or in combination,such as, for example, ratchets, worm-screws, sliding devices,unidirectional sliding devices bidirectional sliding devices,multi-vector sliding devices, rack and pinion devices worm gears and thelike can be used.

The expansion means can be made of any appropriate materials, including,but not limited to metals, ceramics, glass, bioglass, biodegradable,bioerodible, bioresorbable materials and the like. Preferably, atransmitting means is made of a biodegradable, bioerodible orbioresorbable material, such as the material described in U.S. Pat. No.5,919,234 to Lemperle et al., issued Jul. 6, 1999, and as available fromMacropore (San Diego, Calif.). Additional materials include lactic acidpolymers as they are known in the art, such as PLAGA or PLA/PGA(poly-(lactic acid-glycolic acid)).

Any appropriate biodegradable, bioerodible or bioresorbable materialscan be used, so long as they have the desired characteristics, includingbiocompatablility and strength. Although the materials described in U.S.Pat. No. 5,919,234 are perforated, that is not a requirement of thepresent invention. Moreover, an expansion means is preferably heatmalleable such that the material is malleable at a temperature abovethat of the normal body temperature (such as a glass transitiontemperature at about 55° C. to 57° C. or greater, though the inventionis not limited to such ranges of temperatures) and is rigid at bodytemperature (such as about 55° C. to 57° C. or less, though theinvention is not limited to such ranges of temperature). The glasstransition temperature of the material is preferably such that themalleable material, when contacted with a tissue or organ, that tissueor organ is not appreciably damaged.

“Biodegradable” refers to a structure or material that, over time, canbe removed by biological action within the body of a subject such asthey are known in the art or later developed. Biodegradable material caninclude a bioactive compound, such as a pharmaceutical composition, aprotein, a peptide, a nucleic acid molecule or a small molecule.

Such bioactive compounds preferably have desirable activities associatedwith distraction procedures, such as growth factors of various types,bone morphogenic proteins, antibiotics or other compounds to improve orhasten the bone consolidation period or to decrease the time ofdistraction. These bioactive compounds can be leached from thebiodegradable materials over time or be released as the biodegradablematerial is removed by biological action.

“Bioerodible” refers to a structure or material that, over time, can beat least partially removed by biological action within the body of asubject. Preferably, bioerodible materials are removed from the body ofa subject by biological action within between about one month to aboutone year, preferably between about three months and about nine months ofimplantation such as they are known in the art or later developed.

Bioerodible material can include a bioactive compound, such as apharmaceutical composition, a protein, a peptide, a nucleic acidmolecule or a small molecule. Such bioactive compounds preferably havedesirable activities associated with distraction procedures, such asgrowth factors of various types, bone morphogenic proteins, antibioticsor other compounds to improve or hasten the bone consolidation period orto decrease the time of distraction. These bioactive compounds can beleached from the bioerodible materials over time or be released as thebiodegradable material is removed by biological action.

“Bioresorbable” refers to a structure or material that, over time, canbe at least partially removed by biological action within the body of asubject. Preferably, bioresorbable materials are at least partiallyremoved from the body of a subject by biological action within betweenabout one year and about ten years, preferably between about two yearsand about five years of implantation such as they are known in the artor later developed.

Bioresorbable material can include a bioactive compound, such as apharmaceutical composition, a protein, a peptide, a nucleic acidmolecule or a small molecule. Such bioactive compounds preferably havedesirable activities associated with distraction procedures, such asgrowth factors of various types, bone morphogenic proteins, antibioticsor other compounds to improve or hasten the bone consolidation period orto decrease the time of distraction. These bioactive compounds can beleached from the bioresorbable materials over time or be released as thebiodegradable material is removed by biological action.

Biodegradable materials, bioerodible materials and bioresorbablematerials for use in the present invention can be selected from thoseknown in the art or later developed based on their particular biologicalproperties and physical properties. For example, materials preferablyare biocompatible in that they do not stimulate a sustained orsignificant adverse biological response, such as an immunologicalresponse, such as an undesirable macrophage response.

Such materials can be selected using methods known in the art, such asimplantation into test animals or reviews of the literature. Materialspreferably have appropriate tensile strength to withstand the stressedgenerated during distraction. Such materials can be selected usingappropriate methods, such as strength determinations or reviews of theliterature.

A variety of materials, including polymers such as synthetic polymers ornatural polymers, can be suitable for use in the present invention. Forexample, polymers of the following classes are preferred: bioabsorbablebi-component polymers, bacterial polymers and copolymers such aspoly-beta-hydroxy alkonates, polyurethanes, fiber reinforced polymers,self-reinforced polymers, and alpha-hydroxy carbonic acids.

Preferred polymers can also include: Polymers issued from glycolic acidand lactic acids (PLAGA or PLA/PGA) (Vert et al., J. Controlled Release53:85-92 (1998); polylactic acid (J. Oral Maxillofac. Surg. 56:616-626(1998); collagens, aliphatic polyesters, poly(glycolic acid),poly(lactic acid), poly(epsilon-caprolactone) (Hutmacher et al., Int. J.Oral Maxillofac. Implants 11:667-678 (1996); coral/poly(DL-lactic acid)(Li et al., J. Biomater. Sci. Polym. Ed. 7:817-827 (1996); lactic acidpolymers (Merlox et al., Rev. Chir. Orthop. Reparatrice Appar. Mot81:433-444 (1995); co-polymer 85/15 D,L lactide/glycolide (Balch et al.,Arthroscopy 15:691-708 (1999); McGuie et al., Arthroscopy 15:463-473(1999); Kumar et al., J. Craniofac. Surg. 8:97-99 (1997); Pietrazak etal., J. Craniofac. Surg. 8:92-96 (1997); Sinha et al., Drug Dev. Ind.Pharm 24:1129-1138 (1998); Tharanon et al., J. Craniofac. Surg.9:441-444 (1998). Preferred polymers are of the class ofpolyhyproxyorthoesters as supplied by Boehringer Ingelheim.

Additional materials, such as polymers, that may be suitable for use inthe present invention are described in the patent literature: U.S. Pat.No. 5,919,234 to Lemperle, issued Jul. 6, 1999; U.S. Pat. No. 5,935,594,issued to Ringeisen et al., issued Aug. 10, 1999; U.S. Pat. No.5,935,594 to Ringeisen et al., issued Aug. 10, 1999; U.S. Pat. No.5,876,452 to Athanasiou et al., issued Mar. 2, 1999; U.S. Pat. No.5,766,710 to Turnlund et al., issued Jun. 16, 1998; U.S. Pat. No.5,981,619 to Shikinami et al., issued Nov. 9, 1999 (crystallinethermoplastic polymer material, polylactic acid, polyglycolic acid,lactic acid-glycolic acid copolymer and polydioxanone, hydroxylapatite(synthetic or natural, optionally in small amounts); U.S. Pat. No.5,866,155 to Laurencin et al., issued Feb. 2, 1999 (synthetichydroxyapatite, tricalcium phosphate); U.S. Pat. No. 5,697,976 toChesterfield et al., issued Dec. 16, 1997 (polymethylmethacrylate,polymeric hydroxyethylmethacrylate); U.S. Pat. No. 5,876,452 toAthanasiou et al., issued Mar. 2, 1999 (polyanhydrides, poly(orthoesters), aliphatic polyesters, polylactic acid, polyglycolic/polylacticacid mono-and-copolymers); U.S. Pat. No. 5,252,523 to Beall et al.,issued Oct. 12, 1993 (bioabsorbable chlorophosphate and glass-polymerblends); U.S. Pat. No. 5,997,568 to Liu (dioxanone articles, Dexon,Vicryl and Polysorb materials))

A “subject” refers to a human or non-human subject. Non-human subjectscan include experimental, test, agricultural, entertainment or companionanimals.

“Early stabilizing” refers to the stabilization of distracted connectivetissue at a time earlier than expected. Early stabilization can beaccomplished using methods of the present invention. Such stabilizationcan be accomplished, for example, by the early formation of distractedtissue, early differentiation of distracted tissue, or in the case ofbone, early mineralization of tissue.

“Distracted connective tissue” refers to the tissue formed duringdistraction procedure. In the case of bone, distracted connective tissuetends to form a somewhat unstructured, and thus soft, mass, which oftentakes time to strengthen, such as through mineralization.

Introduction

The present invention recognizes that existing distraction devices havecertain disadvantages, including the requirement to remove materials inthe distraction device from the subject's body after distraction iscompleted. Depending on the location of distraction, this procedure canbe of varying degrees of undesirability.

As a non-limiting introduction to the breadth of the present invention,the present invention includes several general and useful aspects,including:

1) a connective tissue distraction device including a first transmittingmeans for transmitting force to a first tissue region and a secondtransmitting means for transmitting force to a second tissue region suchas by contact with bone, expansion means for exerting force distractingsaid first transmitting means from said second transmitting means,wherein one, two or all of said first transmitting means, said secondtransmitting means and said expansion means comprises in whole or inpart a biodegradable, bioerodible or bioresorbable material, preferably,the expansion means is not integral to one or both the firsttransmitting means or the second transmitting means;

2) a method of distracting a first tissue region and a second tissueregion, including implanting the connective tissue distraction device ofthe present invention into a subject and distracting the first tissueregion and the second tissue region;

3) a device for early stabilizing of distracted connective tissue thatincludes a biodegradable, bioerodible or bioresorbable material engagedon or near distracted connective tissue;

4) a method for early stabilizing of distracted connective tissue usinga device that includes a biodegradable, bioerodible or bioresorbablematerial engaged on or near distracted connective tissue; and

5) a method for early stabilizing of distracted connective tissue thatincludes providing biodegradable, bioerodible or bioresorbablematerials, such as mesh, plates or macroporous plates at or near thesite of distraction before and/or during and/or after distractionprocedures such that protected bone regeneration of the distractioncallus can is accentuated.

I. A Connective Tissue Distraction Device

The present invention includes a connective tissue distraction devicethat includes a first transmitting means for transmitting force to afirst tissue region, second transmitting means for transmitting force toa second tissue region and expansion means for exerting forcedistracting said first transmitting means from said second transmittingmeans.

Preferably, one, two or all of said first transmitting means, saidsecond transmitting means and said expansion means comprises in whole orin part a biodegradable, bioerodible or bioresorbable material.Optionally, the expansion means is not integral to one or both of thefirst transmitting means or the second transmitting means.

The first transmitting means and/or the second transmitting means can bethe same or different in any regard, including size, shape andmaterials. The transmitting means can include a structure for attachmentto a tissue region, such as a connective tissue such as bone. Suchstructures can include at least in part a biodegradable, bioerodible orbioresorbable material. Such structures can take any appropriateconfiguration such as those as discussed herein, but preferably include,for example, a plate, including a macroporous plate or a mesh.

The structure for attachment to a connective tissue is attached to atissue region via at least one appropriate attaching device, method ormeans. Preferred attaching structures include screws, staples, pins orstents. The attaching structures are preferably at least in partbiodegradable, bioerodible or bioresorbable material and may be adaptedto any commercially available expansion means, including metallicexpansion means, such as those provided by Leibinger (Carrollton, Tex.)or described in U.S. Pat. No. 5,129,903 to Luhr et al., issued Jul. 14,1992 or U.S. Pat. No. 5,769,850 to Chin, issued Jun. 23, 1998.

The first transmitting means and the second transmitting means arepreferably directly or indirectly engaged or reversibly or irreversiblyengaged to at least one expansion means. The expansion means can be anyappropriate device or structure such as those discussed herein,preferably a screw actuated expansion mechanism, ratchet or slidingplates. Preferably, the expansion means includes in whole or in part abiodegradable, bioerodible or bioresorbable material.

The expansion means can be modulated to draw the first transmittingmeans closer or further away from the second transmitting means. Indoing so, the first tissue region and the second tissue region arebrought closer together or further away. Alternatively, a transmittingmeans and an expansion means can be combined into a single structure,such that there is 1) a transmitting means and 2) a transmitting meansand an expansion means that forms the connective tissue distractiondevice.

In one aspect of the present invention, the first transmitting means 10Aand the second transmitting means 10B comprise structures that allow thetransmitting means 10 to slide unidirectional across each other. The twotransmitting means 10 can slide along a single vector 14 or multiplevectors based on the particular structures used. For example, the firsttransmitting means 10A can comprise engaging structures designed toengage mating structures on the second transmitting means 10B.

For example, the first transmitting means 10A can comprise a pluralityof indentations, holes, protrusions, “shark's teeth” or other structuresthat can engage mating structures on the second transmitting means 10Bsuch as indentations, holes, protrusions or other structures.Preferably, the engaging structures are indentations or holes 16 and themating structures are protrusions such as pins or shark's teethstructures 18.

Alternatively, the engaging structure and the mating structure areshark's teeth structures. As the two transmitting means slide acrosseach other in one direction 14, they engage such that theypreferentially do not slide in a different direction. One preferredexample of this aspect of the invention is depicted in FIG. 10.

In another aspect of the present invention, the connective tissuedistraction device includes guiding means 20 to allow distraction toproceed along a pre-determined vector. For example, a guiding means caninclude a variety of structures to engage at least one portion of atleast one transmitting means, such as tongue and groove configurations.The guiding means are preferable made at least in part of abiodegradable, bioerodible or bioresorbable material. One preferredexample of this aspect of the present invention is provided in FIG. 8.

The connective tissue distraction device can further include anactivation means to modulate the expansion means. The activation meanscan be at least in part external to the subject such that thedistraction device can be adjusted without invasive procedures. Theactivation means can be adjusted using additional materials, such asturn-keys, that activate the expansion means.

The activation means can directly or indirectly engage the expansionmeans, such as by having additional structures between the expansionmeans and the activation means (Leibinger MID System, ScientificDocumentation, Modular Internal Distraction System, Howmedica Leibinger(1998)).

In one aspect of the present invention, the activation means 22 can beengaged with the expansion means 12 at will, such as where theactivation means can engage the expansion means while within the subjectand then be removed at will. Preferably, the activation means is engagedwith the expansion means only for activating the expansion means andthen is removed. The tissues surrounding the expansion means can bestructured using surgical methods known in the art so that theactivating means and the expansion means can be reversibly engaged.

While so engaged, the activation means can activate the expansion means.In one aspect of the present invention, the activation means can includea gear reduction structure, such as between about 1:2 and about 1:50,preferably between abut 1:5 and about 1:20, so that relatively largemovements in the activation means result in relatively smaller movementsin the expansion means.

The use of such gear reduction allows for accuracy and reproducibilityin the distances chosen for distraction procedures. When the activationmeans is removable at will, it is preferred that the transmitting meansand/or expansion means engage using structures 16, 18 that encourageunidirectional displacement, such as provided in FIG. 10.

The activation means 22 need not be permanently engaged with theexpansion means. This is particularly true when the expansion means 12is designed of biodegradable, bioerodible or bioresorbable material andintended to be left in the subject. Under those circumstances, theactivation means is preferably not made of biodegradable, bioerodible orbioresorbable materials can be conveniently disengaged from theremainder of the distraction structure and removed.

In this aspect, the portion of the distraction structure remainingwithin the subject comprises in whole or in part biodegradable,bioerodible or bioresorbable materials. In another aspect of the presentinvention, the activation means and expansion means are integral to eachother can be disengage from one or more transmitting means and removed(see, FIGS. 1-3)

The present invention also includes a connective tissue distractiondevice of the present invention implanted in a subject. When implantedat least on part within the subject, it is preferable that thetransmitting means and the expansion means are internal to the subject.When present, it is preferable that at least a portion of the activationmeans is external to the subject.

II A Method of Distraction

The present invention also includes a method of distracting a firsttissue region and a second tissue region, comprising: implanting theconnective tissue distraction device of the present invention into asubject and distracting the first tissue region and the second tissueregion.

The tissue regions are preferably separated, such as by an accident orby surgical procedures such that bone lengthening is planned anddesired. Tissue regions, such as connective tissues including bone canbe wholly or partially separated using methods known in the art,including osteotomy.

As set forth in FIG. 4, the device of the present invention isappropriately engaged in the subject. The distraction device is thenmodulated using the expansion means 12 and optionally the activationmeans 22 to cause the tissue regions to become further apart. The speedand distance by which the tissue regions are separated by thedistraction device are choices to be made by the surgeon based on theparticular circumstances of a particular case.

A rate of distraction of about 0.5 mm to about 1.0 mm twice a day isrecommended. Distraction continues until the desired distractiondistance has been achieved or circumstances dictate otherwise. Then, thefreshly deposited tissue, when bone, is allowed to mineralize and thusstrengthen.

In the present method, components of the distraction device that are notbiodegradable, bioerodible or bioresorbable are preferably removed afterdistraction is completed. In preferred aspects of the present invention,the transmitting means are made of such biodegradable, bioerodible orbioresorbable materials and thus need not be removed.

If the expansion device is not made of a biodegradable, bioerodible orbioresorbable materials, then that device can be removed by surgical orother methods. Preferably, the expansion means is reversed, such as bythe activating means, to free the expansion means from the transmittingmeans. The expansion means can then be removed with minimal invasiveprocedures.

The activating means can be removed independently of the expansionmeans. This is particularly preferable if the expansion means is made ofa biodegradable, bioerodible or bioresorbable material. In thisinstance, the expansion means and activating means are preferablyreversibly engaged by an appropriate structure as they are known in theart, such as, for example, male-female coupling structures.

III Device for Stabilizing or Early Stabilization of DistractedConnective Tissue

The present invention also includes a device for early stabilizing ofdistracted connective tissue. The device includes a stabilizer thatincludes at least in part a biodegradable, bioerodible or bioresorbablematerial engaged on or near distracted connective tissue. The distractedconnective tissue is preferably bone, but can be other connectivetissues. The stabilizer is preferably within a subject. Due to thebiodegradable, bioerodible or bioresorbable material in the stabilizer,the stabilizer will be at least in part absorbed by the subject and notrequire additional surgical procedures.

One preferred aspect of the present invention includes a stabilizer madeof a macroporous biodegradable material, such as through Macropore (SanDiego). The device is preferably designed to engage at least onetransmitting means such that space between transmitting means is spannedat least in part, preferably in whole, by the stabilizer.

The stabilizer can be engaged with connective tissue, such as bone,using appropriate materials, preferably fasteners made at least in partof biodegradable, bioerodible or bioresorbable material. Preferably, thestabilizer replaces the expansion means when such means are note made ofbiodegradable, bioerodible or bioresorbable materials.

In one aspect of the present invention, the stabilizer replaces at leastone transmitting means and an expansion means. For example, as shown inFIG. 9 the stabilizer would be designed to replace the distal (right)transmitting means and the expansion means by having a shape and sizecorresponding to the combination of the distal transmittingmeans:expansion means combination.

As such, the stabilizer would have a flange that corresponds to themetal flange that engages the notch in the proximal (left) transmittingmeans 10A. As shown in FIG. 9 the stabilizer 24 would correspond to thecombination in the right hand of the model. In this aspect of theinvention, the distal transmitting means and expansion means would beremoved and replaced with the stabilizer.

Optionally, the stabilizer would be designed to replace the proximaltransmitting means. This is the choice of the surgeon, such as on theinvasive nature of the procedure. In the procedure depicted in FIGS. 4and 5, for example, the procedure is much less invasive to remove oralter the distal transmitting means and as such is preferably overremoving or altering the proximal means.

Optionally, the stabilizer can take the shape of at least a portion ofthe combination of the distal transmitting means:expansion meanscombination. In that instance, the distal transmitting means need not beremoved, the expansion means is removed, and the stabilizer is engagedto the connective tissue using appropriate attaching structures 26.

Optionally, the stabilizer would be designed to take the shape of atleast a portion of the combination of the proximal transmittingmeans:expansion means combination. This is the choice of the surgeon,such as on the invasive nature of the procedure. In the proceduredepicted in FIGS. 4 and 5, for example, the procedure is much lessinvasive to modulate the area of the distal transmitting means and asopposed to the area of the proximal transmitting means.

IV Method for Stabilizing or Early Stabilization of DistractedConnective Tissue Using a Stabilizer

Another aspect of the present invention is a method for earlystabilizing of distracted connective tissue that includes performingdistraction on a subject using a distraction device and engaging astabilizer of the present invention with at least one of saidtransmitting means. Preferably, the stabilizer includes at least in parta biodegradable, bioerodible or bioresorbable material, more preferablyof macroporous or other material that promotes bone formation andstrengthening, such as described in U.S. Pat. No. 5,919,234, PLA/PGA oravailable from a variety of commercial sources, such as Macropore (SanDiego, Calif.).

Preferably, the stabilizer is engaged on or near distracted connectivetissue such that distracted tissue is supported and stabilized andallowed to strengthen. The stabilizer can be engaged with a tissueregion using appropriate attachment devices as described herein, whichare preferably made at least in part from biodegradable, bioerodible orbioresorbable materials. The tissue region preferably comprisesconnective tissue, such as bone.

One preferred aspect of the present invention has its basis in theprocedure depicted in FIGS. 4 and 5. Distraction is carried out as setforth in the depicted procedure, resulting in the distraction set forthin FIG. 5. The expansion means 12 is removed, which results inunsupported expansion tissue that is relatively weak. A stabilizer 24 ofthe present invention, as discussed above, can be engaged in a varietyof configurations to replace the expansion means at least in part and/orat least a portion of at least one of the transmitting means.

One preferred aspect of this invention is a stabilizer made ofmacroporous PLA/PGA that corresponds roughly to the size and shape ofthe distal transmitting means, the distracted space, and the expansionmeans, including the flange of the expansion means that engages theflange engaging structures 34 of the proximal transmitting means 10A,such as is shown in FIG. 9.

The distal transmitting means 10B is optionally removed, the stabilizerengaged, and the stabilizer preferably engaged with connective tissue atthe location of the distal transmitting means using appropriateattachment structures or devices as described herein. As discussedabove, the choice of modulating the proximal or distal transmittingmeans is that of the surgeon based on the particular circumstances ofthe case at hand, including the relative invasive nature of the locus ofthe transmitting means, the safety of the procedure, and the desiredresult.

In the alternative, a stabilizer of the present invention can bedesigned to be of a variety of shapes, such as strips, that span thedistracted space. In that instance, the strips are positioned to spanthe distracted space and are secured to the tissue, such as bone oneither side of the distracted space. This step can be performed beforeor after the expansion device is removed. Such materials are preferablymade of macroporous PLA/PGA.

Furthermore, at least one stabilizer can be included in the distractiondevice. The stabilizer is preferably made at least in part ofbiodegradable, bioerodible or bioresorbable material, such as PLA/PGA,preferably macroporous strips or meshes of that material. The stabilizercan be fashioned to be attached to one side of the distraction gap andallowed to slide relatively unabated during the distraction procedure.After distraction is completed, the stabilizer can be attached to theother side of the distraction gap 30. One preferred example of thisaspect of the present invention is depicted in FIG. 7.

V Method for Stabilizing or Early Stabilization of Distracted ConnectiveTissue Using Biodegradable, Bioresorbable or Bioerodible Materials

Another aspect of the present invention is a method for earlystabilizing of distracted connective tissue that includes providingbiodegradable, bioerodible or bioresorbable materials, such as mesh,plates or macroporous plates at or near the site of distraction beforeand/or during and/or after distraction procedures preferably such thatprotected bone regeneration of the distraction callus can isaccentuated.

1. Stabilizing Distracted Connective Tissue—Pre-Distraction Procedures

One method of the present invention is a method for early stabilizing ofdistracted connective tissue, including: providing at least onebiodegradable, bioerodible or bioresorbable material at or near the siteof distraction before a distraction procedure take place and performingdistraction. The material is preferably a material that encourages bonegrowth, development or strengthening, such as macroporous materials ormeshes of materials (such as those described in U.S. Pat. No. 5,919,234,preferably made of PLA/PGA). The material is preferably malleable, suchas heat malleable or chemical malleable, and can also optionally haveshape memory.

In operation, the site to be distracted is covered at least in part withthe material such that during distraction soft tissues and othermaterials are at least preferentially at least partially kept out of thedistraction space. Such materials are fashioned to the distraction sitebefore or after osteotomy procedures, preferably after such procedures.

A distraction device, either of the present invention or otherwise, isthen mounted to the distraction site and distraction takes place asappropriate for the location of the distraction and the type of deviceused. Distraction devices made entirely of metal such as they are knownin the art (see, for example, Leibinger Mid-System documentation90-02104 (December 1998), Howmedia Leibinger, Carrollton, Tex., which isincorporated herein by reference) can be used, as well as thedistraction devices of the present invention.

Other distraction devices known in the art or later developed can alsobe used in these methods. The presence of these materials is expected toaid in the speed of distraction. Although the inventors do not wish tobe limited to any particular mechanism, enhanced speed of distractionmay be attributable to increased speed of bone formation, increasedmechanical stability provided by the material, or increased speed ofmineralization of the distracted tissue.

In one preferred aspect of the invention, the material can form layerswhich slide against each other as distraction proceeds such that thedistraction space is continually covered with material. In one aspect ofthis invention, for example, a rounded long bone is to be distracted,the first transmitting means can be a first cylinder and the secondtransmitting means can be a second cylinder, wherein the first cylinderand second cylinder overlap each other, such as two tubes of differentdiameters would.

As distraction proceeds, the distraction space remains covered by thematerial that overlaps in the two cylinders. Of course, this proceduredoes not require the use of rounded long bones or the use of cylindricaltransmitting means and the procedure can be adapted to otherconfigurations, shapes and locations.

Furthermore, at least one stabilizer can be included in the distractiondevice. The stabilizer is preferably made at least in part ofbiodegradable, bioerodible or bioresorbable material, such as PLA/PGA,preferably macroporous strips or meshes of that material. The stabilizercan be fashioned to be attached to one side of the distraction gap andallowed to slide relatively unabated during the distraction procedure.After distraction is completed, the stabilizer can be attached to theother side of the distraction gap.

2. Stabilizing Distracted Connective Tissue—During Distraction

A further method for early stabilizing of distracted connective tissue,including: providing biodegradable, bioerodible or bioresorbablematerials at or near the site of distraction during distraction. Thematerial is preferably a material that encourages bone growth,development or strengthening, such as macroporous materials or meshes ofmaterials (such as those described in U.S. Pat. No. 5,919,234,preferably made of PLA/PGA). The material is preferably malleable,preferably heat malleable.

In operation, a distraction device is implanted at a distraction sitethe site to be distracted using methods appropriate for the site ofdistraction, the method of distraction and the distraction devicechosen. The material can be attached to the site using methods andprocedures described in U.S. Pat. No. 5,919,234.

During the distraction procedure, especially if the distractionprocedure is not progressing well, the distraction site, preferablyincluding distraction tissue is covered at least in part with thematerial such that during the remainder of distraction soft tissues andother materials are preferentially at least partially kept out of thedistraction space. Distraction devices made entirely of metal as knownin the art can be used, as well as the distraction devices of thepresent invention.

Other distraction devices known in the art or later developed can alsobe used in these methods. The presence of the material can aid in thespeed of distraction. Although the inventors do not wish to be limitedto any particular mechanism, the speed of distraction may beattributable to increased speed of bone formation, increased mechanicalstability provided by the material, or increased speed of mineralizationof the distracted tissue.

3. Stabilizing Distracted Connective Tissue—After Distraction

Another method for early stabilizing of distracted connective tissue,including: providing biodegradable, bioerodible or bioresorbablematerials at or near the site of distraction after distraction has takenplace. The material is preferably a material that encourages bonegrowth, development or strengthening, such as macroporous materials ormeshes of materials (such as those described in U.S. Pat. No. 5,919,234,preferably made of PLA/PGA). The material is preferably malleable,preferably heat malleable.

In operation, the site that has been distracted is covered at least inpart with the material such that soft tissues and other materials arepreferentially at least partially kept out of the distraction space.Such materials are fashioned to the distraction site after distractionis completed. The materials can be fashioned to the location before orafter the distraction device, or a portion thereof, if necessary, hasbeen removed.

Distraction devices made entirely of metal as known in the art can beused, as well as the distraction devices of the present invention. Otherdistraction devices known in the art or later developed can also be usedin these methods. The presence of the material can aid in the speed ofrecovery after distraction is completed. Although the inventors do notwish to be limited to any particular mechanism, the speed of distractionmay be attributable to increased speed of bone formation, increasedmechanical stability provided by the material, or increased speed ofmineralization of the distracted tissue.

VI Preferred Aspects of the Present Invention

This section described a variety of distraction devices wherein at leastone of the elements of the device, including attachment devices, is madein whole or in part of a biodegradable, bioerodible or bioresorbablematerial. The choice of which elements of the distraction device whichare to made in whole or in part of a biodegradable, bioerodible orbioresorbable material depends on the location of the element (such asin the buccal cavity, subcutaneously or in contact with bone) and theresult desired by the surgeon and guided by the present disclosure andthe state of the art.

For example, the materials described in U.S. Pat. No. 5,919,234 may notbe particularly well suited for the buccal cavity. Preferably, plates,support structures such as wires, and means for attaching structures tobone, such as staples, stents, pins and screws, are made in whole or inpart of biodegradable, bioerodible or bioresorbable materials.Furthermore, expansion devices can optionally be made in whole or inpart of such biodegradable, bioerodible or bioresorbable materials.

As will be readily appreciated by those skilled in the art, theexemplary embodiments of the present invention described herein areprovided for the purpose of illustrating practice of the invention butare not intended to limit the scope of the following claims. Numerousmodifications and improvements may be made to the invention withoutdeparting from the spirit and intent of the invention or scope of theclaims.

The very nature of the human tissue formation problems the presentinvention addresses involves substantial variation from patient topatient and therefore requires adaptation of the invention to the needsof each patient. Additionally, a variety of known and yet to bedeveloped materials can be used to practice the invention. Appropriatematerials should have the needed mechanical properties andbio-compatibility for the uses described. Among such materialsappropriate for various components of the invention are stainless steel,titanium, and various polymeric materials, including acrylic materialswidely utilized in dental and orthodontic applications.

Commercially available plate components made of stainless steel,titanium, biodegradable, bioerodible or bioresorbable materials as wellas other materials may be used for the plates described above. Examplesof such components include the plate system components available fromSynthes Ltd. (U.S.A.), Howmedica, Walter Lorenz Surgical Instruments,Inc., Leibinger, MacroPore and others. It will be preferable in someinstances to replace the described plates (which normally cannot be leftin the patient permanently) with implantable osseointegrated componentsto which the force exerting components of the present invention can bereattached multiple times.

Expansion mechanisms having different sizes and methods of action thanthose illustrated and described herein can also be used in practicingthe present invention, and expansion mechanisms actuated otherwise thanwith screws may also be appropriate provided that they are sufficientlycompact to permit intraoral or buried installation of the devicescontemplated by the present invention and allow essentially or entirelynon-invasive periodic incremental adjustment as described above.

For instance, any of the expansion mechanisms, particularly includingthe expansion mechanism of buried distraction device, could utilize abevel-gear actuated jackscrew mechanism so that rotation of an actuationscrew by access to the end of its head coaxial with the screw results inexpansion at right angles to the axis of the action screw. In the caseof buried distraction device, this could permit the use of a smallerchimney penetrating the overlying soft tissue or would permit theactuation screw itself to protrude through an appropriately sleevedchimney to make it accessible for adjustment.

Similarly, cam-acting, ratchet-acting or ratchet and pawl expansionmechanisms could be substituted for the screw-actuated mechanismsdescribed above. As an alternative to all of these, fluidically actuatedexpansion mechanisms using pneumatic or hydraulic cylinders or bladderforce-exerting mechanisms could also be used.

A. Intraoral, Internal Mandibular Bone Distraction Device

An intraoral, internal mandibular bone distraction device id positionedon a human mandible. A mandibular bone distraction device performs intraoral distraction osteogenesis of the mandible in patients withmandibular bone deficiency from a variety of etiologies including butnot limited to: (1) Hemifacial microsomia; (2) Goldenhar's syndrome; and(3) Mandibular deficiency with retrognathism from any other cause.

The mandibular distraction device includes a first transmitting meansthat attaches to the teeth, such as by bonding or cementing usingappropriate materials. The second transmitting means is preferably aplate that is rigidly attached to the mandibular ramus. The firsttransmitting means and the second transmitting means are engaged with anexpansion means used to effect distraction.

The mandibular distraction device can utilize a miniature screwexpansion mechanism as the expansion means. That expansion means caninclude a female slide that receives a male slide, which is movedrelative to female slide by rotation of a double acting jack screw thathas two oppositely threaded ends, one of which is received in a threadedhole in each slide. The jack screw has centrally located trans-axialholes into which a small pin may be inserted in order to rotate thescrew.

Screw expansion mechanisms are referred to as “expansion screws” and maybe obtained in a variety of sizes and configurations from Dentaurum,Inc. 10 Pheasant Run, Newtown, Pa. 18940-1819; RMO Incorporated, P.O.Box 17085, Denver, Colo. 80217; and Turotech, P.O. Box 284, Wynnewood,Pa. 19096. Expansion means such as screw mechanisms may be used singlyor in series or parallel where greater expansion is desired or otherconditions dictate in this aspect or other aspects of the presentinvention.

Mandibular distraction device may be unilateral or bilateral where bothsides of the mandible require lengthening. If the mandibular distractiondevice is bilateral, the first transmitting means may extend across allteeth in the mandible if such a configuration is appropriate.

With the patient under general anesthesia, the mandibular distractiondevice is inserted in the patient's mouth, the first transmitting meansis attached, such as by bonding or cement, to the teeth and the platesare rigidly fixed to the mandible with screws after appropriateincisions in overlying soft tissue make the mandible surface accessible.The surgeon also performs a cut in the mandible or an osteotomy proximalto the mandibular dentition, and the bone is gradually distracted byperiodically cranking the screw expansion device. Osteogenesis takesplace by the principle of Ilizarov or bone lengthening, whereby new boneis formed in between the edges of the bones being gradually distracted.

As will be appreciated by those familiar with prior tissue distractiontechniques, the mandibular distraction device eliminates external scars,is easily placed, avoids the need for tissue penetration on the femaleslide of the device by attachment to the teeth rather than to bone,avoids interference with intraoral structures and function because ofits low profile and can be easily modified for other applications andsituations.

B. Intraoral, Internal Maxillary-Zygomatic-Orbital Distraction Device

A variety of conditions result in malformation or improper growth of themaxillary-zygomatic-orbital region. For instance young patients withcleft lip and palate sometimes exhibit improper maxilla growth. Anotherembodiment of the present invention is an intraoral, internalmaxillary-zygomatic-orbital distraction device. This device has avariety of applications in surgically assistingmaxillary-zygomatic-orbital growth in three dimensions. By use of themaxillary-zygomatic-orbital distraction device, gradual distractionosteogenesis may obviate the need for surgery later or reduce its levelof complexity.

The maxillary-zygomatic-orbital distraction device comprises a firsttransmitting means that is attached to teeth and the second transmittingmeans is a plate. The expansion means preferably comprises two screwexpansion mechanisms that are positioned in the upper buccal sulci. Oneside of each of the screw expansion mechanisms is preferably attached tothe first transmitting means affixed to the maxillary teeth with claspsand resin bonding material or bone cement.

The other side of each expansion means is preferably attached to asecond transmitting means that takes a form of a plate that is rigidlyfixed to the maxilla, zygoma, cranium or orbit as is appropriate for thecondition being treated. As described above in connection with theplates associated with mandibular distraction device, such attachmentmay be accomplished with screws that pass through the plates and intothe bone to which attachment is desired, but any alternative attachmentmeans that results in rigid connection between the bone and proximateside of the screw expansion mechanism will accomplish the desiredresult. For instance, pins or staples into the bone may also bepossible, and adhesive bonding to the surface of the bone may befeasible.

While a maxillary-zygomatic-orbital distraction device is preferablybilateral and utilizes two screw expansion mechanisms as expansionmeans, additional expansion may be desirable in some cases, and only aunilateral device may be required where only distraction of only oneside is desired. Additionally, different positioning of the expansionand second transmitting means such as plates, and different platelengths and shapes may be utilized depending on the site wheredistraction is desired.

The device would be useful for achieving bone growth along a LeFort Iosteotomy. Accordingly, the device is inserted under general anesthesiaand anchored to the maxillary teeth and appropriate bone insubstantially the same manner as the mandibular distraction devicedescribed above. A LeFort I osteotomy is also made and the expansionmechanisms are periodically actuated to permit osteogenesis. As notedabove, the plates can be longer to permit their attachment to thetemporal bones and LeFort II and or LeFort III osteotomies performed toobtain movement of the mid-face and maxilla with osteogenesis at theLeFort II and LeFort III sites.

When maxillary deficiency is corrected, the device can be removed orportions left implanted as osseous implants that can be utilized againif further distraction is necessary.

C. Buried Cranial Distraction Device

A variety of cranial and orbital zygomatic deformities exist, includingbut not limited to: (1) deformational head deformities, (2) torticolliswith deformational head deformities, (3) craniofacial microsomia, and(4) syndromic and nonsyndromic craniosynostosis. In the more commondeformities, the patient presents with an asymmetric head shape becauseof torquing of the cranial base. Generally, the occipital area on oneside is flattened, and there may be contralateral bulging of theforehead with anterior plagiocephaly. In essence, the entire cranialbase is shifted, giving the head a parallelogram shape. The buriedcranial distraction device embodiment of the present invention is usefulin treatment of these deformities.

The internal or buried cranial distraction device of the presentinvention utilized a screw expansion mechanism as an expansion meansattached on each side to the first transmitting means and the secondtransmitting means that take the form of plates that are fixed in placewith screws. The device has a low profile so that it hugs the bone sitewhere it is installed and may be entirely buried under the overlyingsoft tissue.

Alternatively, only the plates may be buried and the expansion means isexternal to the subject, such as when wires penetrate the soft tissueoverlying the bone to which plates are attached so that expansionmechanism lies near but outside of such tissue. Where device is entirelyburied, a small chimney can be formed penetrating the soft tissueimmediately above the actuation holes in the screw to allow insertion ofan appropriately shaped activator to turn the screw in expansion means.

This chimney may, for instance, be lined with a tube or sleeve of anappropriate material such as a stainless steel tube or Dacron, Gortex orother synthetic fabric. It may be covered with a silicon rubber cap oran appropriately formed cover or flap of Dacron, Gortex or othersynthetic fabric or sheet material.

Multiple devices may be placed across the open cranial sutures or whenosteotomies are used across the zygoma or zygomatic-orbital complex ifthe cheekbone and zygomatic orbital region need anterior repositioning.The geometry of the plates may be appropriately configured anddimensioned in a variety of shapes and sized depending on the skullabnormality present and anchorage needed.

The buried cranial distraction device is placed across cranial suturesor across osteotomy lines (for example, orbital and zygomatic) to permitdistraction osteogenesis. By applying the device across the openlambdoid suture, for instance, and gradually distracting the suture byactuation of the expansion mechanism, new bone is laid in between andthe cranial base is gradually repositioned. Multiple devices may benecessary. For instance, one device may be placed across the lambdoidsuture, while a second device is placed across the coronal suture orperhaps on the zygomatic body and arch.

The current treatment of choice for children with severe recession ofthe orbit and forehead secondary to a deformation and not a fused sutureis surgery if the severity of the deformity warrants it. Thus, byplacement of buried distraction devices that can be engaged throughsmall openings in the scalp, the substantial trauma of a combinedneurosurgical and craniofacial surgical procedure is avoided. Inaddition, more precise manipulation of the cranial base structures, theorbit and forehead and the cheek bone, as well as the occiput, willoccur.

D. Intraorbitol Expanding Devices

Patients with microphthalmus or anophthalmia and patients followingenucleation of the globe for a variety of reasons such as trauma,tumors, infection, etc. may require repeated intraorbital prosthesis toprevent cessation of intraorbital growth as the patient ages. A varietyof congenital abnormalities and/or conditions present during childhoodnecessitate placement of a variety of orbital prostheses. Ultimately,the orbital cavity is enlarged to a near symmetric size with acontralateral normal orbit and/or is both orbits are involved to apredetermined adult size.

Following this, the permanent orbital prosthesis can then be placed. Insome cases of microphthalmus or anophthalmia, an orbit itself is madewith bone grafting and/or bone grafting in combination with orbitalosteotomies for expansion. In these cases serial prostheses must also beused to prevent contraction of intraorbital volume. Ultimately, apermanent prosthesis is placed. During serial placement of orbitalprostheses, retention of the prosthesis can be a problem. This may leadto repeated extrusion of the orbital prosthesis.

Additional embodiments of the present invention are intraorbitalexpanding devices. Each of the intraorbital expanding devices areessentially hemispherically shaped bodies segmented into multiplesegments, preferably between about two and about six segments, morepreferably between about two and about four segments and most preferablytwo or three segments. The segments can be solid or hollow. As will beappreciated by those skilled in the art, the segments may be formed ofany material having appropriate mechanical characteristics anddemonstrated biocompatibility. The devices are placed surgically afterappropriate impressions of the eye socket have been taken and the devicefabricated to fit the patient's eye socket.

A screw expansion mechanism is used as an expansion means and attachessegments to be forced apart by rotation of the expansion means, whichpreferably comprises a screw.

Segments are attached by a two-way screw expansion mechanism that hastwo screws that are oriented and operate at right angles to each other.Thus, expansion mechanism is fixed to segment and movably attached tosegments so that rotation of screw causes segment to move relative tosegment along the axis of screw, and rotation of screw causes segment tomove along the axis of screw, which is perpendicular to the direction ofmovement of segment.

Such two-way screw expansion mechanisms, called “multidimensionalexpansion screws” also may be obtained from one or more of the sourcesfor expansion screws identified above. An expansion mechanism that maybe superior to mechanism in the device would move segment along adirection separated 120° from the direction of movement of segment.

The intraorbital expander devices may be fixed in the patient's orbit bya variety of means. For instance screws may be passed through thesegments and into the bone against which those segments rest.Alternatively, projections from the segments can lodge in theintraorbital bone as the devices are expanded, staples can extend fromthe segments to impale adjacent bone as the device opens, plates canconnect the segments to adjacent bone, or the segments can be coveredwith a resilient material such as silicone rubber to lock the device inplace as the segments are separated.

As will also be appreciated by reference to the anatomy of the humanorbit, if the segments are provided with an appropriate recess in whichthe orbital margin seats, the devices will lock themselves in positionas they are expanded where the patient presents with orbital geometrythat is normal or similar to normal in this respect.

Use of the intraorbital expanding device of the present inventionpermits continual expansion without the need for removal and serialplacement of new prostheses. Furthermore, the devices include structuresor geometry for retention that prevent extrusion. As explained above,such structures include either acrylic projections that lodge in theintraorbital bone and/or into notches or drill holes made by theinserting surgeon, and/or by metallic stapling devices pinned againstand into the orbital bone.

E. Intraorbitol, Buccal Tissue Expanding Device

Patients with vestibular tissue deficiency secondary to burns, trauma,tumor resection, mandibular atrophy secondary to loss of teeth, and avariety of other causes often require vestibuloplasty. This may belimited to the anterior region or the posterior vestibule. This may berelated both to the mandibular, lower buccal sulcus, and the maxillaryupper buccal sulcus. Patients with congenital deformities such as cleftlip and palate and other craniofacial deformities may also have tissuedeficiencies in these areas.

Current treatment involves a vestibuloplasty by releasing the scarredand contracted vestibular tissue and bringing in new tissue either bymeans of rotation flaps or tissue grafting or free tissue transfer.Following correction of vestibular tissue deficiencies, and intraoralstent is usually manufactured and placed.

Often this is fixated to the teeth by means of stainless steel claspsand occasionally a variety of other fixation devices, usually circamandibular and/or maxillary suspension wires. The stent itself istypically left in for prolonged periods in order to prevent contractionof the newly introduced tissue and recurrence of the original problem.Such devices are either not adjustable or are not easily adjusted.

Another embodiment of the present invention is an intraoral, buccaltissue expanding device. Such a device may be used followingvestibuloplasty, grafting, free tissue transfer, as a preliminaryexpanding device, or as the sole means of tissue expansion. The detailsof the appropriate structure for buccal tissue expanding device will, asis the case with the other embodiments of the present inventiondescribed above, depend on the particular needs of the patient for whomthe device is made.

Exemplary mandibular device is bilaterally symmetrical and thereforewill be described primarily by reference to one side, in this case theright side. A tooth stent forms the first transmitting means is bondedto the mandibular teeth and is connected through a triple-actingexpansion mechanism forming the expansion means to a posterior tissueexpanding stent and an anterior tissue expanding plate that serve as thesecond transmitting means.

A curved buccal tissue expanding stent is attached to the anteriorexpanding plate or stent. The device is attached to the teeth by bondingor cementing the tooth stent to the mandibular teeth so that the stentspress against the new vestibular tissue.

Rotation of screw in expansion mechanism causes lateral movement ofposterior and anterior tissue expanding stents to permit exertion ofdesired pressure on adjacent tissue. Rotation of double-acting screw inexpansion mechanism causes posterior movement of posterior tissueexpanding stent and anterior movement of both anterior tissue expandingstent and buccal tissue expanding stent. Such adjustment of thepositions of stents results in active tissue expansion to preventcontraction of newly introduced vestibular tissues.

EXAMPLES Example I Biodegradable Distraction Device for Use inMandibular Distraction, LeFort III Distraction, Le Forte I Distractionor Monobloc Distraction Methods

As depicted in FIGS. 1-6, the present invention can be used in a widevariety of distraction surgical methods and procedures. Although some ofthe components of the device in FIG. 1-6, are represented as metal orother non-biodegradable, bioerodible or bioresorbable materials,biodegradable, bioerodible or bioresorbable materials can be used forany of these components.

Preferably, the activating means 22 is not made of such biodegradable,bioerodible or bioresorbable materials, but that need not be the case.The activating device 22 is depicted without a turn-key, which whenturned one rotation clockwise results in a distraction of about 0.5 mm.

A variety of surgical procedures may employ the internal biodegradabledistraction device of the present invention including for examplemonobloc distraction with and without facial bipartition and otherosteotomies, LeFort III distraction with or without subcranial facialbipartition, LeFort II, LeFort I, zygomatic and mandibular distraction.Since the system is biodegradable additional substantial surgicalprocedures will not be required to remove the implanted device. Thefollowing is a general description of a distraction procedure using oneaspect of a distraction device of the present invention.

A bioerodible polymer mesh (Macropore, Inc. San Diego, Calif.) isutilized to secure the device to bone. The mesh is attached to eitherside of the metallic screw of the expansion mechanism by bioerodibleslots that retain the footplate of the metallic screw. The bioerodibleslots in turn are attached to the mesh with biodegradable screws. Themesh is heat malleable, consequently it may be cut and contoured to fitvirtually any anatomical site. Standard osteotomies are performed.

The osteotomy is spanned with the distractor that is attached to thebone with biodegradable mesh and screws. Test distraction is performedto determine the total distraction distance and to ensure that there isno evidence of detachment of the biodegradable mesh and screws. Testdistraction also enables the surgeon to determine if the osteotomy iscomplete and the bone segment to be transported is fully mobilized.

Distraction is initiated on post-operative days 5-7 and carried out atapproximately 1.0 mm per day divided into two sessions per day.Preoperative radiologic and clinical findings dictate the extent ofdistraction. Intraoperative test distraction also enables the surgeon todetermine the extent of distraction that will be necessary forcorrection of the particular deformity. Careful postoperative follow-upenables the surgeon to determine when distraction is complete.

Unlike the large exposure that is necessary to remove metallic screws,the biodegradable device permits easier removal if necessary. Themetallic distraction screw that is activated and driven by an externalcable sheathed in TEFLON is turned counterclockwise. The footplates ofthe distraction screw slide out of the biodegradable slots. The meshdoes not require removal and usually degrades within about 18 to 36months after implantation.

Once distraction is complete the metallic distraction screw is rotatedclockwise until it is disengaged from the distraction footplate andremoved from the patient. Under direct or endoscopic exposure, a newbioerodible stabilizer is placed into the anterior biodegradable slot ofthe attachment part which is attached to the biodegradable mesh or plateand screwed into the posterior bone segment. This permits earlierremoval of the device and rigid stabilization of the osteotomies anddistraction callus, permitting bony consolidation. All wounds are closedunder standard medical procedures.

FIG. 4 depicts a region of a skull that has undergone an osteotomy tofully free a portion of the “cheek bone.” This freed region is theregion to be distracted during the procedure. As shown in FIG. 1 depictstwo portions of a transmitting means includes a macroporous sheet 32 ofPLA/PGA and a flange-engaging structure 34 suitable for engaging aflange of an expansion means 12.

In this aspect of the present invention the first transmitting means 10Aand the second transmitting means 10B have substantially similarstructures. The particular structures of the flange-engaging structure34 are provided in FIG. 6A-6C. As shown in FIG. 1 the flange-engagingstructure 34 can be engaged to the macroporous sheet 32 usingappropriate attaching devices 36, in this case bioresorbable PLA/PGAscrews.

Two transmitting means 10 of FIG. 1 can be engaged with engaged with anexpansion means 12 that includes flanges that engage the flange-engagingstructures 34 of the transmitting means (FIGS. 2-3). In this figure, theexpansion means 12 is depicted as being made of non-biodegradable,non-bioerodible or non-bioresorbable materials, but that need not be thecase because the expansion means can be made of such biodegradable,bioerodible or bioresorbable materials in whole or in part.

As shown in FIG. 3, the nature of the engagement of the transmittingmeans and the expansion means as reversible. In the pictured aspect ofthe present invention, this reversible engagement is exhibited for boththe first transmitting means and the second transmitting means. Thus,after distraction is accomplished, the expansion means can be disengagedfrom the remainder of the distraction device and removed.

It is relatively simple to remove the expansion means from a subject asopposed to the transmitting means. Thus, there is a reduced amount ofcumulative trauma that the subject is exposed to. The proximaltransmitting means:expansion means:distal transmitting means has beentrimmed and configured for use on the osteotomy depicted in FIG. 4. Notethat the proximal transmitting means has been altered from its planarconfiguration.

The transmitting means has a heat malleable nature, and a transmittingmeans is contacted with water hot enough to induce malleability of thematerial and the shape of the material is changed to conform to theshape of the region to which it will be attached. As shown in FIG. 4,the distraction device is depicted in place at the site of osteotomyprior to distraction.

The distraction device includes heat-malleable materials that have beenmolded to the contours of the attachment points of the distractiondevice. The transmitting means 10 are secured to the skull using PLA/PGAscrews in holes drilled into the bone. During a distraction procedure,the implementation of the distraction device would be complete.Distraction would be accomplished by engaging the expansion means 12with an activation means 22 to gradually increase the distractiondistance.

FIG. 5 depicts the distraction device after distraction has taken place.This figure depicts a mock-up skull, thus the distraction space has notbeen filled with distraction tissue. At this point in the procedure, theexpansion means 12 would be removed by disengaging the expansion means12 from the transmitting means 10, such as by engaging the activationmeans 22 to decrease the length of the expansion device. The expansionmeans can be removed using surgical procedures, preferably endoscopicprocedures. If the expansion means is made in whole or in part ofbiodegradable, bioerodible or bioresorbable materials, then theexpansion means can optionally be removed.

Optionally, at least one stabilizer 24, 28 can be inserted into, over oraround the expansion space and appropriately secured such that thedistracted tissue is mechanically stabilized (FIG. 7 or FIG. 9). Suchstabilizer(s) are preferably made at least in part of biodegradable,bioerodible or bioresorbable material, such as PLA/PGA, preferablymacroporous PLA/PGA. In one aspect of the present invention, thestabilizing means can engage structures on the transmitting means 10A(FIG. 9).

In one aspect of the present invention, the stabilizing means of FIG. 7and FIG. 9 can be combined. In addition, guiding means 20 can be usedduring distraction or after distraction to guide or stabilize thedistraction device (FIG. 8). The guiding means is preferably made inwhole or in part of a biodegradable, bioerodible or bioresorbablematerial.

As shown in FIG. 8, a preferred aspect of the present invention is aguiding means that engages both the first and second transmitting means,but that is not a requirement of the present invention. For example, theguiding means can be attached to a tissue structure in proximity to thedistraction site, such as bone.

In one aspect of the present invention alternative structures of FIG. 10depict a unidirectional distraction device that includes engagingstructures 18 such as those in “shark's tooth” configurations and matingstructures 16 to match the engaging structures such as indentations orholes (such as those in macroporous structures) to allow substantiallyunidirectional sliding of the transmitting means and can act tostabilize the distraction device. Preferably, the engaging structuresand/or the mating structures are made in whole or in part ofbiodegradable, bioerodible or bioresorbable materials.

The engaging structures and mating structures can be provided on anyappropriate surface on a distraction device that come in contact or inclose proximity to each other. For example, the first and secondtransmitting means can be designed to overlap each other during at leasta portion of a distraction procedure. Alternatively, the expansion meanscan overlap with one or both of the first or second transmitting meansduring at least a portion of a distraction procedure.

All publications, including patent documents and scientific articles,referred to in this application and the bibliography and attachments areincorporated by reference in their entirety for all purposes to the sameextent as if each individual publication were individually incorporatedby reference.

All headings are for the convenience of the reader and should not beused to limit the meaning of the text that follows the heading, unlessso specified.

In the preceding detailed description, reference is made to theaccompanying drawings, which form a part hereof, and in which is shownby way of illustration specific embodiments in which the invention maybe practiced. In this regard, directional terminology, such as “top,”“bottom,” “front,” “back,” “leading,” “trailing,” etc., is used withreference to the orientation of the Figure(s) being described. Becausecomponents of embodiments can be positioned in a number of differentorientations, the directional terminology is used for purposes ofillustration and is in no way limiting. It is to be understood thatother embodiments may be utilized and structural or logical changes maybe made without departing from the scope of the present invention. Thepreceding detailed description, therefore, is not to be taken in alimiting sense, and the scope of the present invention is defined by theappended claims.

It is contemplated that features disclosed in this application, as wellas those described in the above applications incorporated by reference,can be mixed and matched to suit particular circumstances. Various othermodifications and changes will be apparent to those of ordinary skill.

The invention claimed is:
 1. A method for early stabilizing ofdistracted connective tissue, comprising: at least partially covering adistraction site with biodegradable, bioerodible or bioresorbablematerials before a distraction procedure takes place, wherein thebiodegradable, bioerodible or bioresorbable materials comprise a firstimplant, a second implant and a third implant; attaching the firstimplant and the second implant to a distraction site; engaging the firstimplant and the second implant with a sliding expansion mechanism;performing distraction on a connective tissue at the distraction siteusing the sliding expansion mechanism to exert a force to distract thefirst implant from the second implant; disengaging the sliding expansionmechanism from the first implant and the second implant; and stabilizingthe distracted connective tissue by attaching the third implant to thefirst implant and the second implant.
 2. The method of claim 1, whereinthe distraction site remains at least partially covered with thebiodegradable, bioerodible or bioresorbable materials while performingdistraction.
 3. The method of claim 1, wherein the biodegradable,bioerodible or bioresorbable materials at least partially keep softtissues and other materials out of the distraction site.
 4. The methodof claim 1, wherein the at least two pieces continually cover thedistraction site while performing the distraction.
 5. The method ofclaim 1, wherein the first implant and the second implant each have acylindrical shape and wherein the first implant and the second implanteach have a different diameter.
 6. The method of claim 1, wherein thesliding expansion mechanism comprises at least one of a screw, aratchet, a unidirectional sliding device, a bidirectional slidingdevice, a multi-vector sliding device, a rack and pinion device, a wormgear or combination thereof.
 7. The method of claim 1, wherein the stepof stabilizing the distracted connective tissue comprises stabilizingthe distracted connective tissue with a macroporous material.
 8. Themethod of claim 1, wherein the step of stabilizing the distractedconnective tissue comprises stabilizing the distracted connective tissuewith a malleable material.
 9. A method for early stabilizing ofdistracted connective tissue, comprising: at least partially covering adistraction site with biodegradable, bioerodible or bioresorbablematerials before a distraction procedure takes place, wherein thebiodegradable, bioerodible or bioresorbable materials comprise a firstimplant, a second implant and a third implant; attaching the firstimplant and the second implant to the distraction site; engaging thefirst implant and the second implant with a sliding expansion mechanism;performing distraction on a connective tissue at the distraction site,wherein the first implant and the second implant move with respect toeach other performing the distraction; and stabilizing the distractedconnective tissue by attaching the third implant to the first implantand the second implant.
 10. The method of claim 9, wherein thedistraction site remains at least partially covered with thebiodegradable, bioerodible or bioresorbable materials while performingdistraction.
 11. The method of claim 9, wherein the biodegradable,bioerodible or bioresorbable materials at least partially keep softtissues and other materials out of the distraction site.
 12. The methodof claim 9, wherein the first implant and the second implant continuallycover the distraction site while performing the distraction.
 13. Themethod of claim 9, wherein the first implant and the second implant eachhave a cylindrical shape and wherein the first implant and the secondimplant each have a different diameter.
 14. The method of claim 9,wherein the sliding expansion mechanism comprises at least one of ascrew, a ratchet, a unidirectional sliding device, a bidirectionalsliding device, a multi-vector sliding device, a rack and pinion device,a worm gear or combination thereof.
 15. The method of claim 9, andfurther comprising disengaging the sliding expansion mechanism from thefirst implant and the second implant after the distraction is complete.16. The method of claim 9, wherein the step of stabilizing thedistracted connective tissue comprises stabilizing the distractedconnective tissue with a macroporous material.
 17. The method of claim9, wherein the step of stabilizing the distracted connective tissuecomprises stabilizing the distracted connective tissue with a malleablematerial.